If it is the abdomen and not the stomach area i would say its from the heat. if you've ever seen a dead animal on the side of the road over the course of a few days, they start to swell from the sun beating down on them all day.
Speed up chemical reactions (Catalysts)
Arthritis
Arthritis is a joint disorder in
which there is inflammation of one or more joints. Arthritis is frequently accompanied by joint
pain. There are many types of arthritis and over 100 have been identified. The causes
of arthritis include injury, metabolic abnormalities, hereditary factors,
effect of infections, and a misdirected immune system. Arthritis is mostly
common among women and occurs as people get older. Severe arthritis can result
in chronic pain, inability to do daily activities and can cause difficulty in walking.
The correct answer is - a front.
On this image, the lines are representing a front, and since the signs are marked with blue color, it means that it is a cold front. The fronts are advancing masses of air. In this case, we have a cold front, thus we have advancing cold air masses in the western part of the US, and in the Great Lakes region and the northeastern part of the country. This means that these areas will be affected by colder air masses, that will bring in higher air pressure, colder weather, and cold winds from the direction from which these cold fronts are coming.